U.S. Pat. No. 7,438,396 B2 discloses a continuous ink jet printer having an array of nozzles for simultaneously printing across the width of a substrate, such as a textile fabric. For each nozzle there is (i) a droplet formation section, such as a piezoelectric transducer, (ii) a droplet charging section, such as parallel metal plates, and (iii) a droplet deflection section, for directing the path of the droplet to the desired location on a substrate to be printed. The range of deflection of the droplets is such that adjacent nozzles can overlap, to print a seamless pattern on the substrate. The deflection plates are spaced apart and oppositely charged, for example at 1 to 5 kV, to produce an electrical field. The charge on the droplets and/or the strength of the electrical field created by the deflection plates can be varied, to create more or less deflection of the droplet. In one example, uncharged droplets are not deflected and collect in the gutter.
During operation of the printer, liquid can collect on the surface of the deflection plates, leading to arcing between the plates and a subsequent disruption of the electrical field and printer electronics.